To download a PDF of this blog with an overview of CGM Apps covered too, please click here.
Do you want to know how to avoid hypos?
Sleep better at night? Improve your quality of life?
And manage your diabetes so to avoid medical complications?
The secret is that many T1s are likely to be using a Bubble, MiaoMiao or BluCon. If you’ve wondered about these devices, here’s our guide to help you understand the lingo, why you would want one and what you need to consider before purchasing such a device.
What is a CGM?
CGM is the anacronym for continuous glucose monitor and there are 3 elements to a CGM device. Firstly, there’s the sensor that contains a filament that sits beneath the skin and measures interstitial fluid; secondly there’s a transmitter that picks up the data using NFC (near field communication); and then a reader that receives the data from the transmitter, interprets it and displays the glucose level readings on the reader. This can also be a phone that is capable of receiving data by NFC.
To use a CGM effectively the user also needs access to an App that displays the readings, usually as a log and graph. The App enables users to download other charts and reports that will provide data showing results, patterns and trends relating to the user’s glucose levels over time.
A CGM will send glucose level readings every 5 minutes to the reader or phone continuously i.e. ongoing through the day and night. Data is translated by a proprietary algorithm (software owned by the developer of the App) and displayed on the user’s device. The CGM has the capability to alert a user to high and low levels through an alarm.
Although a Libre sensor does not require calibration, a CGM may need the user to calibrate it, by carrying out a finger prick test, to ensure the levels it gives are ‘accurate’.
FreeStyle Libre as a CGM
The Libre is often referred to as a CGM but is in fact a flash glucose monitoring system as it relies on the user to scan the sensor to receive the readings stored in the sensor.
Although the Libre brings huge benefits to wearers, there are principally 3 features ‘missing’ when using the Libre 1sensor.
- Continuity of seeing readings - without the need to scan!
- Alarms - crucial to many wearers and their carers to alert them to highs and lows;
- Ability to share information with another person / carer.
These are the main advantages offered when converting the Libre to a full CGM but are not the only features sought. Many wearers convert so that they can see their numbers without having to scan their device, and to see them on a smart watch. Other adaptions I’ve heard of include connecting up to an Alexa or Google to be able to ask about glucose levels and displaying the readings from the sensor on a car’s instrumental panel.
Converting to a CGM
In order to be able to convert the Libre to a full CGM you will need a transmitter that can read the Libre sensor using Bluetooth. It’s important to note here that although widely done by many Libre wearers and known and even accepted by many health professionals too, the use of transmitters and the associated Apps are not medically approved and would breach the manufacturer’s warranty. None of these products referred to below are recommended by Freestyle Libre and are untested by Abbott.
What are the options?
For the Freestyle Libre, there are currently 3 main options – transmitters - that can be used to convert your Libre into a true CGM: the MiaoMiao, Bubble and Nightrider BluCon. In terms of manufacture, both the MiaoMiao and Bubble are manufactured in China, so use Chinese technology. The BluCon NightRider is manufactured in the USA.
Each of these 3rd party transmitters has a different form and attaches to the Libre sensor in a different way. Evaluating how you will wear the transmitter is an important consideration as well as the App that you will use that will provide the data and alarms.
Wearing a transmitter changes the overall look of the sensor on your arm (or other site) and here I’ve modelled how each device looks.
3rd Party Apps
Once you have a transmitter device, or preferably before making your decision on which to choose, you should consider the Apps available. All of which have their own. Other Apps are not compatible with every device so it’s advisable to check which app you will use in advance of buying the device.
For MiaoMiao the manufacturer’s app is called Tomato and is available to download on both the Google Play store and Apple’s App store.
Bubblan (a seller of Bubble) have an app called Diabox which is on Google Play for android phones, and for access through an iphone you need to download and accept the terms of TestFlight using the app in beta format.
Ambrosia Systems recommends its App, Link BluCon for readings from the BluCon Nightrider. The app is available on both Google Play store and Apple’s App store.
It’s also a timely point here to mention that you do need to be a little technical-minded to install some of the 3rd party apps. Third party apps you may see mentioned include Xdrip (available for Android and IOS), Spike, Glimp and Nightscout. Using a CGM device and third-party app will usually require the user to calibrate their readings.
Will Libre 2 be a full CGM?
There’s much anticipation in the online T1 community for the Libre 2 which has now been released in limited European countries and the US although the App is at the time of writing this article, waiting for FDA approval so data is only to a reader device. There’s no official launch date for the updated device in the UK as it’s awaiting approval for funding but is now imminent and is expected to replace Libre 1 on NHS prescriptions.
The main difference with the Libre 2 is that it will have alarms to alert users to high and low glucose levels. The alarms will work independently of scanning the device, although users still need to scan to receive regular updates to glucose levels and all related data.
The future and Libre 3
Abbott have just announced that they have received a CE mark for the Libre 3, enabling them to role this out in the European market. Libre 3 will give users full CGM with readings sent every minute to a compatible smartphone, without the need to scan. The sensor has had a size change and is now 70% smaller and the thinnest sensor on the market, approximately the size of 2 US pennies on top of each other.
In the UK as we are still awaiting the rollout of Libre 2 it’s not known when these will be available, but we are told that the NHS are in ‘discussions’ with Abbott. The cost is expected to be the same as Libre 1 and 2.
Keep scanningEven if you convert your Libre to CGM, you will still probably need to scan your sensor regularly to ensure your healthcare professional can see your glucose levels and access reports from your data.
Sometimes providing this data is part of the contract with the NHS for funding and it also helps the NHS to collate data which is used to evaluate the effectiveness of prescribing the sensor as a treatment and to assess ongoing funding and budgets.
PS. We have a full comparison of the three transmitters available to users in the UK in our blog “ COMPARING MIAOMIAO2, BUBBLE AND BLUCON”.
Click this link to download the table https://indd.adobe.com/view/541769d5-09fe-463d-8421-33fb13866f8f
All transmitters were purchased personally and I have not been provided with any incentive to promote or endorse any of these products in any way. All views are my own. I have no connection to any of the companies providing the transmitters or Abbott® or FreeStyle Libre®.